It is incredibly hard to spot the rattling component, even if you get underneath with a prybar.
Simple example. I poly'd the upper arms and replaced the drop links on my 156. 2 weeks later it was clattering. I lift her up, and take a pry bar to everything, including the ARB. No problem. I noticed that the undertray was a bit loose, so refixed that and test drove. Still rattled. So I lifted it again, and went over every nut that I had undone - and one of the ARB drop link nuts was a fraction too loose. Nipped it up half a turn, and all was silent.
Droplinks are disposable service items - almost every other year for me.